air expands with in the heat and compresses in the cold. if you were to have 32psi in the winter, you'll have much more than that in the spring. the volume of air you put into your tires on a 0 degree day will be greater than the volume of air you do on a 100 degree day.

it's not that you physically keep your tires under 32psi during a certain time of year ... you have to monitor the psi during climate shifts.